Almost immediately after the race, Pistorius criticized Oliveira for using unusually long prosthesis.
On Monday, Pistorius apologized for the timing of his comments, but insisted Oliveira had an unfair advantage because of the length of his artificial legs.
"I would never want to detract from another athlete's moment of triumph and I want to apologize for the timing of my comments," Pistorius said in a statement. "I do believe that there is an issue here and I welcome the opportunity to discuss it with the [International Paralympic Committee], but I accept that raising these concerns immediately as I stepped off the track was wrong. That was Alan's moment and I would like to put on record the respect I have for him."
Pistorius had won gold in the 200 in the previous two Paralympics and said he was shocked to lose to Oliveira.
"He's never run a 21-second race and I don't think he's a 21-second athlete," Pistorius said of Oliveira, who won Sunday's race in 21.45 seconds. "I've never lost a 200-meter race in my career."
On Monday, the IPC said that Oliveira's prosthesis had been approved before the race.
Oliveira said he only started using his current blades 3 weeks ago, and that he felt "let down" by Pistorius' comments.
It will be interesting to see how the rest of the Paralympics plays out. The two compete against each other three more times this week.